The production of high pressure decorative laminates has expanded in recent years to the extent that millions of square feet of product are now being produced annually. These laminates are used for furniture, cabinetry, vertical surfaces and the like. Ordinarily, the laminates are produced by heat and pressure consolidating at least one kraft paper core sheet which has been impregnated with a thermosetting phenol/formaldehyde resin and a decorative sheet that is impregnated with a melamine/formaldehyde resin which does not undergo any noticeable color deterioration upon subsequent lamination. The decorative sheet is usually dyed or pigmented to a selected color or it may have printed thereon a specific design, pattern, etc., such as a geometric figure or a floral design. The printed matter may also constitute a wood grain print such that the finished laminate represents naturally occurring wood. Frequently, the decorative sheet has a fine quality paper impregnated with a color stable thermosetting resin as an overlay sheet thereupon which acts as a barrier to avert abrasion of the decorative sheet and thus preserve its printed character.
The trend in recent years has been toward extremely thin, light weight, low cost decorative laminates which are somewhat flexible, dimensionally stable and resistant to cracking and/or glue line failure. In accordance with the trend, U.S. Pat. Nos. 3,547,769 and 3,589,974 have recently set forth variations in the production of such laminates wherein overlay sheets are omitted and resin layers are substituted therefor, or different paper sheets, e.g., acrylic paper, have been employed. The properties of decorative laminates have also been varied by the incorporation of resins other than only melamine/formaldehyde or phenol/formaldehyde into the decorative and core sheets, see U.S. Pat. Nos. 3,218,225 and 3,220,916.